WO2018003742A1

WO2018003742A1 - Data-processing device, tablet printing apparatus, data-processing method, and tablet printing method

Info

Publication number: WO2018003742A1
Application number: PCT/JP2017/023406
Authority: WO
Inventors: 信行中野; 内田　直樹
Original assignee: 株式会社Ｓｃｒｅｅｎホールディングス
Priority date: 2016-06-28
Filing date: 2017-06-26
Publication date: 2018-01-04
Also published as: CN109195803B; CN109195803A; KR20190004746A; JP2018000282A; JP6811555B2; KR102176136B1

Abstract

The present data-processing device (80) is for preparing print data (D5) for printing on the surfaces of tablets using an inkjet head. The data-processing device (80) comprises a vector-rotating section (81) and an image-transforming section (82). The vector-rotating section (81) vector-rotates input vector data (D1) and prepares multiple vector-rotated data (D2) that correspond to multiple rotation angles. The image-transforming section (82) transforms each of the vector-rotated data (D2) to raster data (D3). It is thereby possible to limit the occurrence of reduced print quality due to image rotation. As a result, it is possible to limit the occurrence of reduced print quality in tablet printing devices. Accordingly, it is possible to improve print quality in inkjet-mode tablet printing devices.

Description

Data processing apparatus, tablet printing apparatus, data processing method, and tablet printing method

The present invention relates to a data processing apparatus and a data processing method for creating print data used in a tablet printing apparatus for printing on the surface of a tablet, and a tablet printing apparatus and a tablet printing method.

文字 Characters and codes for product identification are printed on the surface of tablets that are pharmaceuticals. Such characters and codes may be printed by engraving. However, the engraving has a problem of low visibility. In particular, in recent years, the types of tablets have been diversified due to the spread of generic drugs. For this reason, in order to identify a tablet reliably, performing clear printing on the surface of a tablet is calculated | required.

In recent years, orally disintegrating tablets that can be taken without using water have gradually become widespread. Orally disintegrating tablets are vulnerable to pressure. Therefore, it is preferable to perform printing without applying pressure when printing on orally disintegrating tablets. For this reason, attention has been paid to a technique for printing an image on the surface of a tablet by an inkjet method. In an ink jet tablet printing apparatus, an image can be printed on the surface of a tablet more clearly than engraving. Further, an image can be printed in a non-contact manner without applying pressure to the surface of the tablet.

In recent years, the secant lock that can be divided along the secant line has become widespread. When printing on tablets having directionality such as scored tablets and capsule tablets, it is necessary to perform printing in a direction corresponding to the direction of each tablet for a plurality of tablets to be conveyed. For example, Patent Document 1 discloses a conventional ink jet type tablet printing apparatus that performs printing in consideration of the direction of a tablet.

Japanese Patent Laying-Open No. 2015-223323

In an inkjet tablet printing device, dots are arranged in a vertical and horizontal grid to represent an image. For this reason, in the tablet printing apparatus of the ink jet system, the surface of the tablet is used by using the printing data in which the selection of whether or not to discharge the ink droplets and the selection of the size of the ink droplets is performed in each region arranged in a grid pattern on the surface of the tablet. An image is formed on.

In such an ink jet type tablet printing apparatus, when the print image is rotated in consideration of the orientation of the tablet, even if the basic print data is simply rotated, the ink droplet ejection position in the print data and the ink jet head are not the ink droplets. There is a case where the area where ink can be discharged does not match. For this reason, if the basic print data that is simply rotated is used, the print quality may be reduced as compared with the case where non-rotated print data is used.

This invention is made in view of such a situation, and it aims at providing the technique which can improve printing quality in the tablet-type printing apparatus of an inkjet system.

In order to solve the above problems, a first invention of the present application is a data processing apparatus for creating print data for performing print processing on the surface of a tablet by an ink jet head, and an input vector A vector rotation processing unit that rotates the data vector to generate a plurality of vector rotation data corresponding to a plurality of rotation angles, and an image conversion processing unit that converts each of the vector rotation data into raster data.

A second invention of the present application is the data processing device according to the first invention, further comprising a thinning processing unit that converts each of the plurality of raster data into thinning data having a smaller number of ink ejection pixels than the raster data. The raster data is data in which the ink discharge amount is determined for each of the regions arranged in a grid pattern, and the ink discharge region in which ink is discharged in the thinning data is more than the ink discharge region in the raster data. Is also small.

A third invention of the present application is the data processing apparatus according to the second invention, wherein the thinning-out processing unit alternates between the ink discharge area and the ink non-discharge area in a portion where the ink discharge area of the raster data is continuous. The thinned-out data is generated by converting the pattern into the pattern arranged in the above.

A fourth aspect of the present invention is the data processing apparatus according to the third aspect, wherein the thinning-out processing unit includes a rectangular ink discharge region and a rectangular shape in which the ink discharge region of the raster data is continuous. The thinning data is generated by converting the ink non-ejection area into a pattern alternately arranged.

A fifth invention of the present application is a tablet printing apparatus for printing on the surface of a tablet, comprising a data processing device for creating print data and a plurality of nozzles for ejecting ink droplets, toward the surface of the tablet An inkjet head that performs printing processing by ejecting the ink droplets, a camera that is disposed upstream of the head and that detects a rotation angle of the tablet, and a control unit that controls ejection of the ink droplets from the head The data processing device comprises a vector rotation processing unit that vector-rotates input vector data and generates a plurality of vector rotation data corresponding to a plurality of rotation angles, and rasterizes each of the vector rotation data. An image conversion processing unit for converting into data, and the data processing device outputs a plurality of print data based on the plurality of raster data, and controls the control. A print data holding unit that holds a plurality of print data corresponding to the rotation angle, and the print data holding unit that selects and selects the print data based on the rotation angle detected by the camera A print processing unit that causes the head to perform print processing based on the print data, and the print data holding unit is input from the data processing device before the rotation angle is detected by the camera. A plurality of the print data are held.

A sixth invention of the present application is the tablet printing apparatus according to claim 5, wherein the data processing device converts each of the plurality of raster data into thinned data having a smaller number of ink ejection pixels than the raster data. The raster data is data in which an ink discharge amount is determined for each of the regions arranged in a grid pattern, and the ink discharge region in which ink is discharged in the thinning data is The raster image data is smaller than the ink ejection area in the raster data, and the data processing device outputs a plurality of the thinned data as the print data, and the print data holding unit has the rotation angle before the detection of the rotation angle by the camera. A plurality of the print data input from the data processing device are held.

A seventh invention of the present application is the tablet printing apparatus according to the sixth invention, wherein the thinning-out processing unit alternates between the ink discharge area and the ink non-discharge area in a portion where the ink discharge area of the raster data is continuous. The thinned-out data is generated by converting the pattern into the pattern arranged in (1).

An eighth invention of the present application is the tablet printing apparatus according to the seventh invention, wherein the thinning-out processing unit includes a rectangular ink discharge region and a quadrangular ink discharge region in which the ink discharge region of the raster data is continuous. The thinning data is generated by converting the ink non-ejection area into a pattern alternately arranged.

A ninth invention of the present application is a data processing method for creating print data for performing print processing on the surface of a tablet by an ink jet head, and a) vector rotation of input vector data A step of generating a plurality of vector rotation data corresponding to a plurality of rotation angles, and b) a step of converting each of the plurality of vector rotation data into raster data.

A tenth invention of the present application is the data processing method according to the ninth invention, further comprising the step of c) converting each of the plurality of raster data into thinned data having a smaller number of ink ejection pixels than the raster data. The raster data is data in which the ink discharge amount is determined for each of the regions arranged in a grid pattern, and the ink discharge region in which ink is discharged in the thinning data is more than the ink discharge region in the raster data. Is also small.

An eleventh invention of the present application is the data processing method according to the tenth invention, wherein, in the step c), the thinned-out data includes a portion where the ink discharge region of the raster data is continuous, the ink discharge region and the ink non-discharge region. It is generated by converting into a pattern in which discharge areas are alternately arranged.

A twelfth invention of the present application is the data processing method according to the eleventh invention, wherein, in the step c), the thinned-out data includes a portion of the raster data where the ink discharge region is continuous, and the rectangular ink discharge region. And a square-shaped non-ejection region of ink are converted into a pattern alternately arranged.

A thirteenth invention of the present application is a tablet printing method in which a printing process is performed on the surface of a tablet by an ink jet head, and A) a plurality of vectors corresponding to a plurality of rotation angles by rotating the input vector data. According to the rotation angle based on the raster data obtained in the step B), the step of generating the vector rotation data of B), the step of B) converting each of the plurality of vector rotation data into raster data, and C) A step of holding a plurality of print data, D) a step of detecting the rotation angle of the tablet after the step C), and E) a plurality of steps based on the rotation angle after the step D). Selecting the print data to be used for the printing process from the print data of F, and F) forming an image on the surface of the tablet based on the print data selected in the step E) And a step of printing, the.

A fourteenth aspect of the present invention is the tablet printing method according to the thirteenth aspect of the present invention, in which G) after the step B) and before the step C), each of the plurality of raster data is obtained from the raster data. In the step C), a plurality of the thinned data is held as a plurality of the print data, and the raster data is arranged in a grid pattern. The ink discharge amount is determined for each region, and the ink discharge region in which ink is discharged in the thinning data is smaller than the ink discharge region in the raster data.

A fifteenth aspect of the present invention is the tablet printing method according to the fourteenth aspect, wherein, in the step G), the thinning data includes a portion where the ink discharge area of the raster data is continuous, the ink discharge area and the ink non-printing area. It is generated by converting into a pattern in which discharge areas are alternately arranged.

A sixteenth aspect of the present invention is the tablet printing method according to the fifteenth aspect, wherein, in the step G), the thinning data includes a region where the ink discharge region of the raster data is continuous, and the rectangular ink discharge region. And a square-shaped non-ejection region of ink are converted into a pattern alternately arranged.

According to the first to sixteenth aspects of the present invention, raster data obtained by rasterizing vector data obtained by vector rotation in advance is used as print data. Thereby, it can suppress that the image quality falls by rotation of an image. As a result, it is possible to suppress a decrease in print quality in the tablet printing apparatus.

According to the second invention to the fourth invention, the sixth invention to the eighth invention, the tenth invention to the twelfth invention, and the fourteenth invention to the sixteenth invention of the present application, the mottling is performed during the printing process in the tablet printing apparatus. Generation | occurrence | production can be suppressed. Therefore, it is possible to further suppress the deterioration of print quality in the tablet printing apparatus.

It is the figure which showed the structure of the tablet printing apparatus. FIG. 6 is a perspective view of the vicinity of a transport drum. It is a bottom view of a head. It is the block diagram which showed the connection of a control part, each part in a tablet printing apparatus, and a data processor. FIG. 3 is a block diagram conceptually showing a configuration relating to a printing process corresponding to a rotation angle in the tablet printing apparatus and data processing apparatus 80. It is the flowchart which showed the flow of the data processing in a data processor. It is the figure which showed the example which rasterized the non-rotated vector data. FIG. 6 is a diagram illustrating an example in which vector data is rotated after rasterization and then rasterized again. It is the figure which showed the example rasterized after vector rotation of vector data. It is a conceptual diagram which shows a mode that the ink droplet was discharged to the site | part which an ejection area | region continues. It is a conceptual diagram which shows a mode that the ink droplet was discharged to the site | part which an ejection area | region continues. It is a conceptual diagram which shows a mode that the ink droplet was discharged to the site | part which an ejection area | region continues. In an experiment, it is the figure which showed the relationship between the conveyance speed and the occurrence state of a mottling for every droplet size and pattern. It is the figure which showed an example of the thinning pattern. It is the figure which showed an example of the thinning data using the thinning pattern shown in FIG. It is the figure which showed an example of the thinning pattern. It is the figure which showed an example of the thinning data using the thinning pattern shown in FIG. It is the figure which showed an example of the thinning pattern. It is the figure which showed an example of the thinning data using the thinning pattern shown in FIG. It is the figure which showed an example of the thinning pattern. It is the flowchart which showed the flow of the printing process in a tablet printer. FIG. 6 is a diagram illustrating an example of print data stored in a print data holding unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, a direction in which a plurality of tablets are transported is referred to as a “transport direction”, and a direction perpendicular to the transport direction is referred to as a “width direction”.

<1. Configuration of tablet printing device>
FIG. 1 is a diagram showing a configuration of a tablet printing apparatus 1 according to an embodiment of the present invention. The tablet printing apparatus 1 is an apparatus that prints an image such as a product name, a product code, a company name, and a logo mark on the surface of each tablet 9 while conveying a plurality of tablets 9 that are medicines. As shown in FIG. 1, the tablet printing apparatus 1 of this embodiment includes a hopper 10, a feeder unit 20, a transport drum 30, a first printing unit 40, a second printing unit 50, a carry-out conveyor 60, and a control unit 70. .

The hopper 10 is an input unit for receiving a large number of tablets 9 in the apparatus. The hopper 10 is disposed at the top of the housing 100 of the tablet printing apparatus 1. The hopper 10 has an opening 11 located on the upper surface of the housing 100 and a funnel-shaped inclined surface 12 that gradually converges as it goes downward. The plurality of tablets 9 put into the opening 11 flows into the rectilinear feeder 21 along the inclined surface 12.

The feeder unit 20 conveys the plurality of tablets 9 put into the hopper 10 to the conveyance drum 30. The feeder unit 20 of the present embodiment includes a linear feeder 21, a rotary feeder 22, and an inclined feeder 23. The rectilinear feeder 21 has a flat vibration trough 211. The plurality of tablets 9 supplied from the hopper 10 to the vibration trough 211 are conveyed to the rotary feeder 22 side by the vibration of the vibration trough 211. The rotary feeder 22 has a disk-shaped rotary table 221. The plurality of tablets 9 that have dropped from the vibration trough 211 onto the upper surface of the turntable 221 are collected near the outer periphery of the turntable 221 by centrifugal force generated by the rotation of the turntable 221.

The inclined feeder 23 has a plate-like slope 231 that extends obliquely downward from the outer periphery of the turntable 221 to the transport drum 30. FIG. 2 is a perspective view of the vicinity of the transport drum 30. As shown in FIG. 2, a plurality of conveying grooves 232 are provided on the upper surface of the slope 231. In the example of FIG. 2, eight conveyance grooves 232 are provided on the upper surface of the slope 231. The plurality of tablets 9 transported to the outer peripheral portion of the turntable 221 are respectively supplied to any one of the plurality of transport grooves 232 and flow down obliquely downward along the transport grooves 232. As described above, the plurality of tablets 9 are aligned and supplied to the plurality of transport rows by being distributedly supplied to the plurality of transport grooves 232. Then, the plurality of tablets 9 in each conveyance row are supplied to the conveyance drum 30 in order from the first one.

The transport drum 30 is a mechanism that delivers a plurality of tablets 9 from the inclined feeder 23 to the first transport conveyor 41. The conveyance drum 30 has a substantially cylindrical outer peripheral surface. The conveyance drum 30 is rotated in the direction of the arrow in FIGS. 1 and 2 around a rotation axis extending in the width direction by power obtained from a motor (not shown). As shown in FIG. 2, a plurality of suction holes 31 are provided on the outer peripheral surface of the transport drum 30. The plurality of suction holes 31 are arranged along the circumferential direction on the outer peripheral surface of the transport drum 30 at the position in the width direction corresponding to each of the plurality of transport rows described above.

A suction mechanism (not shown) is provided inside the transport drum 30. When the suction mechanism is operated, a negative pressure lower than the atmospheric pressure is generated in each of the plurality of suction holes 31. The suction holes 31 suck and hold the tablets 9 supplied from the inclined feeder 23 one by one by the negative pressure. In addition, a blow mechanism (not shown) is provided inside the transport drum 30. The blow mechanism blows locally pressurized gas from the inside of the transport drum 30 toward the first transport conveyor 41 described later. As a result, the suction of the tablets 9 is released only in the suction holes 31 facing the first transport conveyor 41 while maintaining the suction state of the tablets 9 in the suction holes 31 not facing the first transport conveyor 41. Thus, the transport drum 30 rotates while adsorbing and holding the plurality of tablets 9 supplied from the inclined feeder 23, and can transfer these tablets 9 to the first transport conveyor 41.

A first secant detection camera 32 is provided on the outer periphery of the transport drum 30. The first secant detection camera 32 is an imaging unit that captures the state of the tablet 9 before printing. The first secant detection camera 32 images the tablet 9 transported by the transport drum 30 and transmits the obtained image to the control unit 70. Based on the received image, the control unit 70 detects the presence / absence of the tablet 9 in each suction hole 31, the front and back of the tablet 9 held in the suction hole 31, and the rotation angle.

The first printing unit 40 is a processing unit for printing an image on one surface of the tablet 9. As shown in FIG. 1, the first printing unit 40 includes a first conveyor 41, a second secant detection camera 42, a first head unit 43, a first inspection camera 44, and a first fixing unit 45.

The first transport conveyor 41 is a transport mechanism having a pair of pulleys 411 and an annular transport belt 412 that is stretched between the pair of pulleys 411. The conveyor belt 412 is disposed so that a part thereof is opposed to the outer peripheral surface of the conveyor drum 30. One of the pair of pulleys 411 is rotated by power obtained from a motor (not shown). As a result, the conveyor belt 412 rotates in the direction of the arrow in FIGS. At this time, the other of the pair of pulleys 411 rotates following the rotation of the conveyor belt 412.

As shown in FIG. 2, the conveying belt 412 is provided with a plurality of suction holes 413. The plurality of suction holes 413 are arranged in the transport direction at the position in the width direction corresponding to each of the plurality of transport rows. That is, the plurality of suction holes 413 are arranged at intervals in the width direction and the transport direction. The spacing in the width direction of the plurality of suction holes 413 in the transport belt 412 is equal to the spacing in the width direction of the plurality of suction holes 31 in the transport drum 30.

The conveying belt 412 is provided with a suction mechanism (not shown). When the suction mechanism is operated, a negative pressure lower than the atmospheric pressure is generated in each of the plurality of suction holes 413. The suction holes 413 suction and hold the tablets 9 delivered from the transport drum 30 one by one by the negative pressure. Thereby, the 1st conveyance conveyor 41 conveys the several tablet 9, hold | maintaining in the state aligned in the some conveyance row | space spaced in the width direction. Further, the transport belt 412 is provided with a blow mechanism (not shown). When the blow mechanism is operated, the air pressure in the suction holes 413 facing the second transport conveyor 51 described later becomes a positive pressure higher than the atmospheric pressure. Thereby, the adsorption of the tablet 9 in the suction hole 413 is released, and the tablet 9 is delivered from the first transport conveyor 41 to the second transport conveyor 51.

The second secant detection camera 42 is an imaging unit that captures the state of the tablet 9 before printing on the upstream side of the first head unit 43 in the transport direction. The second secant detection camera 42 images the tablets 9 transported by the first transport conveyor 41 and transmits the obtained image to the control unit 70. Based on the received image, the control unit 70 detects the presence / absence of the tablet 9 in each suction hole 413 and the front and back surfaces and the rotation angle of the tablet 9 held in the suction hole 413.

The first head unit 43 is an ink jet head unit that ejects ink droplets toward the surface of the tablet 9 that is transported by the first transport conveyor 41. The first head unit 43 has four heads 431 arranged along the transport direction. The four heads 431 eject ink droplets of different colors (for example, cyan, magenta, yellow, and black) toward the surface of the tablet 9. A multicolor image is recorded on the surface of the tablet 9 by superimposing single-color images formed by these colors. In addition, the edible ink manufactured by the raw material approved by the food hygiene law is used for the ink discharged from each head 431.

FIG. 3 is a bottom view of one head 431. In FIG. 3, the transport belt 412 and the plurality of tablets 9 held by the transport belt 412 are shown by two-dot chain lines. As shown enlarged in FIG. 3, a plurality of nozzles 430 capable of ejecting ink droplets are provided on the lower surface of the head 431. In the present embodiment, a plurality of nozzles 430 are two-dimensionally arranged on the lower surface of the head 431 in the transport direction and the width direction. The nozzles 430 are arranged at different positions in the width direction. In other words, each of the plurality of nozzles 430 is disposed at a different position in the width direction. Thus, if the plurality of nozzles 430 are two-dimensionally arranged, the positions in the width direction of the nozzles 430 can be brought closer to each other. However, the plurality of nozzles 430 may be arranged in a line along the width direction.

As a method for ejecting ink droplets from the nozzle 430, for example, a so-called piezo method is used in which a voltage is applied to a piezo element, which is a piezoelectric element, and the ink in the nozzle 430 is pressurized and ejected. The head 431 of this embodiment can switch the size of the ink droplets ejected from the nozzles 430 depending on the magnitude of the voltage applied to the piezo element. Specifically, there are three types of ink droplets: “small size” which is the smallest and fine ink droplet, “large size” which is the largest ink droplet, and “medium size” which is an intermediate size ink droplet. Of these, arbitrary ink droplets can be ejected. However, the size of ink droplets that can be ejected may be one or two types, or four or more types. Further, the ink droplet ejection method may be a so-called thermal method in which the ink in the nozzle 430 is ejected by heating and energizing the heater.

Return to Figure 1. The first inspection camera 44 is an imaging unit for confirming the printing result by the first head unit 43. The first inspection camera 44 images the surface of the plurality of tablets 9 transported by the first transport conveyor 41 on the downstream side in the transport direction with respect to the first head unit 43, and sends the obtained image data to the control unit 70. Send. Based on the received image data, the control unit 70 determines whether or not the image printed on the surface of each tablet 9 has a printing defect such as misalignment or missing dots.

The first fixing unit 45 is a mechanism for fixing the ink discharged from the first head unit 43 to the tablet 9. In the present embodiment, the first fixing unit 45 is disposed downstream of the first inspection camera 44 in the transport direction. However, the first fixing unit 45 may be disposed between the first head unit 43 and the first inspection camera 44. For the first fixing unit 45, for example, a hot air drying heater that blows hot air toward the tablets 9 conveyed by the first conveyance conveyor 41 is used. The ink adhering to the surface of the tablet 9 is dried by hot air and fixed on the surface of the tablet 9.

The second printing unit 50 is a processing unit for printing an image on the other surface of the tablet 9 after printing by the first printing unit 40. As shown in FIG. 1, the second printing unit 50 includes a second transport conveyor 51, a third dividing line detection camera 52, a second head unit 53, a second inspection camera 54, and a second fixing unit 55. The second transport conveyor 51 transports while holding the plurality of tablets 9 delivered from the first transport conveyor 41. The third secant detection camera 52 images the plurality of tablets 9 transported by the second transport conveyor 51 on the upstream side of the second head unit 53 in the transport direction. The second head unit 53 discharges ink toward the surface of the tablet 9 that is transported by the second transport conveyor 51. The second inspection camera 54 images the surface of the plurality of tablets 9 that are transported by the second transport conveyor 51 on the downstream side of the second head unit 53 in the transport direction. The second fixing unit 55 fixes the ink discharged from each head 531 of the second head unit 53 to the tablet 9.

The details of each of the second conveyor 51, the third dividing line detection camera 52, the second head unit 53, the second inspection camera 54, and the second fixing unit 55 are as described above. Since this is equivalent to the camera 42, the first head unit 43, the first inspection camera 44, and the first fixing unit 45, a duplicate description is omitted.

The unloading conveyor 60 is a mechanism for unloading a plurality of tablets 9 after printing out of the casing 100 of the tablet printing apparatus 1. The upstream end of the carry-out conveyor 60 is located below the second transfer conveyor 51. The downstream end of the carry-out conveyor 60 is located outside the housing 100. For the carry-out conveyor 60, for example, a belt conveyance mechanism is used. After the printing process in the second printing unit 50, the plurality of tablets 9 fall from the second transport conveyor 51 to the upper surface of the carry-out conveyor 60 by releasing suction of the suction holes. Then, the plurality of tablets 9 are carried out of the housing 100 by the carry-out conveyor 60.

The control unit 70 controls the operation of each unit in the tablet printing apparatus 1. FIG. 4 is a block diagram showing the connection between the control unit 70 and each unit in the tablet printing apparatus 1. As conceptually shown in FIG. 1, the control unit 70 is configured by a computer having an arithmetic processing unit 701 such as a CPU, a memory 702 such as a RAM, and a storage unit 703 such as a hard disk drive. A computer program P for executing print processing is installed in the storage unit 703.

As shown in FIG. 4, the control unit 70 includes the above-described linear feeder 21, the rotary feeder 22, the transport drum 30 (including a motor, a suction mechanism, and a blow mechanism), the first secant detection camera 32, and the first transport. Conveyor 41 (including a motor, a suction mechanism, and a blow mechanism), a second secant detection camera 42, a first head unit 43 (including a plurality of nozzles 430 of each head 431), a first inspection camera 44, and a first fixing unit 45, a second conveyor 51, a third dividing line detection camera 52, a second head unit 53 (including a plurality of nozzles of each head 531), a second inspection camera 54, a second fixing unit 55, and an unloading conveyor 60; Each is connected so that it can communicate. The control unit 70 is connected to the data processing device 80 so as to be communicable.

The control unit 70 temporarily reads the computer program P and data D stored in the storage unit 703 into the memory 702, and the arithmetic processing unit 701 performs arithmetic processing based on the computer program P, whereby each of the above-described units. Control the operation. Thereby, the printing process with respect to the some tablet 9 advances.

The data processing device 80 processes the print data input to the tablet printing device 1. As conceptually shown in FIG. 1, the data processing device 80 is configured by a computer having an arithmetic processing unit 801 such as a CPU, a memory 802 such as a RAM, and a storage unit 803 such as a hard disk drive. A computer program Pd for executing data processing is installed in the storage unit 803.

The data processing device 80 temporarily reads the computer program Pd and data Dd stored in the storage unit 803 into the memory 802, and the arithmetic processing unit 801 performs arithmetic processing based on the computer program Pd, which will be described later. Perform data processing. As a result, data processing for creating print data proceeds.

<2. Configuration of Data Processing Device and Control Unit>
Next, detailed configurations of the data processing device 80 and the control unit 70 of the tablet printing device 1 will be described. Print data D5 created by the data processing device 80 is input to the control unit 70 of the tablet printing device 1. The tablet printing apparatus 1 performs a printing process corresponding to the rotation angle of the tablet 9 based on the print data D5. FIG. 5 is a block diagram conceptually showing a configuration relating to a printing process corresponding to the rotation angle of the tablet printing apparatus 1 and the data processing apparatus 80.

As shown in FIG. 5, the data processing device 80 of this embodiment includes a vector rotation processing unit 81, an image conversion processing unit 82, and a thinning processing unit 83. The functions of the vector rotation processing unit 81, the image conversion processing unit 82, and the thinning processing unit 83 are realized by the computer as the data processing device 80 operating according to the computer program Pd described above.

The input data D1 that is vector data representing an image to be printed is input to the vector rotation processing unit 81 from the outside. The vector rotation processing unit 81 vector-rotates the input data D1 at a plurality of predetermined rotation angles. Thus, the vector rotation processing unit 81 generates a plurality of vector rotation data D2 corresponding to a plurality of rotation angles.

In the vector rotation processing unit 81 of this embodiment, the input data D1 is vector-rotated every 2 ° to generate vector rotation data D2. That is, the vector rotation processing unit 81 generates 180 vector rotation data D2 whose rotation angles are 0 ° (no rotation), 2 °, 4 °, 6 °,. The rotation angle for generating the vector rotation data D2 is not limited to every 2 °. The rotation angle for generating the vector rotation data D2 may be every 1 °, every 1.5 °, every 3 °, or every other angle.

The image conversion processing unit 82 rasterizes each of the plurality of vector rotation data D2 generated by the vector rotation processing unit 81 and converts it into raster data D3. As a result, a plurality of raster data D3 corresponding to a plurality of rotation angles is generated. The raster data D3 is data in which the ink discharge amount is determined for each region arranged in a grid pattern.

The thinning processing unit 83 converts each of the plurality of raster data D3 generated by the image conversion processing unit 82 into the thinning data D4. Thereby, a plurality of thinning data D4 corresponding to a plurality of rotation angles is generated. The thinning data D4 is raster data having a smaller number of pixels (hereinafter referred to as “ink ejection pixel number”) that should eject ink than the raster data D3. That is, the area in which ink is to be ejected in the thinning data D4 (hereinafter referred to as “ink ejection area”) is smaller than the ink ejection area in the raster data D3.

The data processing device 80 of the present embodiment outputs a plurality of thinned data D4 generated by the thinning processing unit 83 to the control unit 70 of the tablet printing device 1 as a plurality of print data D5. However, the present invention is not limited to this. The plurality of print data D5 output to the control unit 70 may be data based on the plurality of raster data D3. For example, the data processing apparatus of the present invention may not have the thinning processing unit 83. In that case, the data processing device 80 outputs the raster data D3 generated by the image conversion processing unit 82 to the control unit 70 of the tablet printing device 1 as print data D5.

Note that when the printing process is performed on both the front surface and the back surface of the tablet 9 as in the tablet printing device 1 of the present embodiment, the data processing device 80 uses the front surface print data D5 and the back surface print data D5. It is necessary to generate both.

Also, the control unit 70 of the present embodiment includes a print data holding unit 71, a rotation angle detection unit 72, a print data selection unit 73, and a discharge control unit 74. The function of the print data holding unit 71 is realized by the storage unit 703 described above. The functions of the rotation angle detection unit 72, the print data selection unit 73, and the discharge control unit 74 are realized by the computer as the control unit 70 operating according to the computer program P described above.

The print data holding unit 71 holds a plurality of thinned data D4 input from the data processing device 80 as a plurality of print data D5. When a plurality of raster data D3 is input as a plurality of print data D5 from the data processing device 80, the print data holding unit 71 holds the plurality of raster data D3 as a plurality of print data D5.

The rotation angle detection unit 72 uses the tablet 9 held in each suction hole 413 of the first transport conveyor 41 based on the image data D6 of the tablet 9 input from the first secant detection camera 32 and the second secant detection camera 42. Presence / absence, front / back and rotation angle are detected. Further, the rotation angle detection unit 72 is configured so that each of the second conveyors 51 is based on the image data D6 of the tablets 9 input from the first secant detection camera 32, the second secant detection camera 42, and the third secant detection camera 52. The presence / absence, front / back, and rotation angle of the tablet 9 held in the suction hole are detected.

The print data selection unit 73 selects print data D5 to be printed on each tablet 9 from a plurality of print data D5 held in the print data holding unit 71 based on the detection result D7 of the rotation angle detection unit 72, and discharges the data. Delivered to the control unit 74.

The ejection control unit 74 controls the ejection of ink from each nozzle of the first head unit 43 and the second head unit 53 based on the print data D5 received from the print data selection unit 73, and the ink is applied to the surface of each tablet 9. To discharge.

<3. Flow of data processing in data processing device>
Hereinafter, the flow of the printing process according to the rotation angle in the data processing device 80 and the tablet printing device 1 will be described with reference to FIG. FIG. 6 is a flowchart showing the flow of data processing in the data processing device 80. Prior to printing processing in the tablet printing apparatus 1 to be described later, data processing of the data processing apparatus 80 shown in FIG. 6 is performed.

As shown in FIG. 6, in the data processing of the data processing device 80, first, input data D1, which is vector data, is input to the vector rotation processing unit 81 (step S101).

Next, the vector rotation processing unit 81 vector-rotates the input data D1 to a plurality of predetermined rotation angles to generate a plurality of vector rotation data D2 (step S102).

Subsequently, the image conversion processing unit 82 rasterizes each of the plurality of vector rotation data D2 to generate a plurality of raster data D3 (step S103).

Here, the order of rotation and rasterization of vector data will be described with reference to the examples of FIGS. FIG. 7 is a diagram showing an example of rasterizing non-rotated vector data. FIG. 8 is a diagram showing an example in which vector data is rotated after rasterization and then rasterized again. FIG. 9 is a diagram showing an example in which vector data is rasterized after vector rotation. In FIG. 7 to FIG. 9, it is rasterized to binary data.

In the tablet printing apparatus 1 that is an inkjet printer, ink droplets are ejected from the inkjet heads 431 and 531 for each of the ink ejection regions arranged in a vertical and horizontal grid pattern. As a result, one ink droplet is ejected for each ink ejection region. For this reason, in the printing process in the tablet printing apparatus 1, it is necessary to prepare print data that defines the presence or absence of ink droplets and the size of ink droplets for each ink ejection region. Therefore, it is necessary to convert the input vector data into raster data expressed for each pixel arranged in a vertical and horizontal grid pattern.

When the rotation angle is 0 ° (no rotation), as shown in FIG. 7, it is not necessary to rotate the image data. Therefore, raster data obtained by simply rasterizing vector data can be used as printing data.

When the rotation angle is other than 0 °, it is necessary to rotate image data at any timing and prepare raster data rasterized in a predetermined direction as final print data.

As shown in FIG. 8, when generating the raster rotation data by rotating the first raster data obtained by rasterizing the vector data, the pixels of the raster rotation data are arranged in a grid inclined with respect to the vertical and horizontal directions. Is done. For this reason, the raster rotation data cannot be used as printing data. Therefore, in order to convert the raster rotation data into pixel data in the vertical and horizontal directions, it is necessary to rasterize again. The second raster data obtained by re-rasterization has a large backlash compared to the raster data when the rotation angle is 0 ° (no rotation). For this reason, when printing is performed using the second raster data, the print quality may be deteriorated.

Therefore, as shown in FIG. 9, the data processing apparatus 80 of the present embodiment generates raster data by rasterizing vector rotation data obtained by vector rotation of vector data. By doing so, it is possible to obtain raster data having the same quality as when the rotation angle is 0 ° (no rotation). Therefore, it is possible to suppress a decrease in print quality.

When the print quality deteriorates due to rotation, it is not possible to use a strict threshold when inspecting the print result by the

inspection cameras

44 and 54. As described above, if the deterioration of the print quality due to the rotation is suppressed, the

inspection cameras

44 and 54 can inspect the print result using a strict threshold. Accordingly, it is possible to further suppress a decrease in print quality.

After the image conversion processing unit 82 generates a plurality of raster data D3 in step S103, the thinning processing unit 83 converts each of the plurality of raster data D3 to generate a plurality of thinned data D4 (step S104). Then, the thinned data D4 is output as the print data D5 to the control unit 70 of the tablet printing apparatus 1 (step S105).

Here, the conversion processing by the thinning processing unit 83 will be described with reference to FIGS. 10 to 12 are conceptual diagrams showing a state in which ink droplets are ejected to a portion where the ejection area of the raster data D3 is continuous. FIG. 10 is a diagram illustrating an example in which “medium” ink droplets are ejected over the entire ink ejection region. FIG. 11 is a diagram illustrating an example in which “small size” ink droplets are ejected over the entire ink ejection region. FIG. 12 shows an example in which the ink ejection area is converted into an area in which the ink ejection area and the ink non-ejection area are alternately arranged, and “medium” ink droplets are ejected to the converted ink ejection area. FIG. In FIGS. 10 to 12, each square area surrounded by a straight line is an area corresponding to one ink droplet.

When the tablet 9 is a tablet having a glossy surface such as a sugar-coated tablet, the ejected ink droplets easily move on the surface of the tablet 9. For this reason, a phenomenon called “mottling” in which ink droplets flow and connect to adjacent ink droplets easily occurs. Mottling tends to occur as the conveyance speed of the tablet 9 increases. FIG. 10 shows an ink flow portion 92 in which mottling occurs and the adjacent ink droplets 91 are connected and flow.

In order to reduce the occurrence of mottling, as shown in FIG. 11, a method of reducing the size of the ink droplet 91 ejected to each of the ink ejection regions can be used. Further, in the present invention, as shown in FIG. 12, a method is used in which continuous ink discharge regions are converted into ones in which ink discharge regions and non-discharge regions are alternately arranged so that the ink discharge regions are not continuous. . Hereinafter, as shown in FIGS. 10 and 11, a pattern in which ink ejection regions are continuous is referred to as a solid pattern. Further, as shown in FIG. 12, a pattern in which the ink ejection areas and the non-ejection areas are alternately arranged is referred to as a checkered pattern.

FIG. 13 is a diagram showing the relationship between the transport speed and the state of occurrence of mottling for each droplet size and pattern in an experiment performed using the tablet printing apparatus 1 of the present embodiment. In FIG. 13, “medium / solid” indicates that a solid pattern is printed with ink droplets of “medium” as shown in FIG. “Small size / solid”, as shown in FIG. 11, shows a case where a solid pattern is printed with ink droplets of “small size”. “Medium size / checkered” indicates a case where a checkered pattern is printed with ink droplets of “medium” as shown in FIG. In FIG. 13, “◯” indicates a state in which no mottling has occurred, “Δ” indicates a state in which the amount of mottling is not more than a predetermined amount, and “×” indicates that the amount of mottling is not less than a predetermined amount. In some situations, “-” indicates that no experiment was performed.

As shown in FIG. 13, “small size / solid” has a higher conveyance speed at which mottling occurs than “medium / solid”. That is, “small size / solid” is less likely to cause mottling than “medium / solid”. In addition, in “medium / checkered”, the conveyance speed at which mottling occurs is higher than that in “small / solid”. In other words, “middle / checkered” is less likely to cause mottling than “small / solid”. From this, it can be seen that the pattern in which the ink ejection regions and the non-ejection regions are alternately arranged is very effective in suppressing the occurrence of mottling.

Thus, by reducing the number of ink discharge areas, the occurrence of mottling is suppressed. Therefore, in the data processing device 80 of the present embodiment, in step S104, the plurality of raster data D3 is converted into thinned data D4 having a smaller number of ink ejection pixels than each raster data D3. And it can suppress that a mottling generate | occur | produces at the time of the printing process in the tablet printing apparatus 1 by using this thinning-out data D4 as printing data.

Further, the use of a pattern in which the ink discharge areas and the non-discharge areas are alternately arranged as described above further suppresses the occurrence of mottling. Therefore, in the data processing device 80 of the present embodiment, in step S104, the plurality of raster data D3 is converted into a plurality of thinned data D4 in which the ink ejection regions and the non-ejection regions are alternately arranged. By using such thinning data D4 as print data, it is possible to further suppress the occurrence of mottling during the printing process in the tablet printing apparatus 1. Further, by using such thinning data D4 as printing data, the ink ejected onto the tablet 9 can be quickly dried. Furthermore, the amount of ink used can be reduced by using such thinning data D4 as print data.

Here, some examples of patterns actually used for the thinned data D4 are introduced. FIG. 14 is an example of a 50% thinning pattern. FIG. 15 is an example of the thinning data D4 using the 50% thinning pattern shown in FIG. The pattern in the example of FIGS. 14 and 15 is a so-called checkered pattern in which one ink ejection region and one non-ejection region are alternately arranged in the vertical direction and the horizontal direction. When such a pattern is used, the number of ink ejection pixels in the thinned data D4 is about 50% of the number of ink ejection pixels in the raster data D3.

FIG. 16 is an example of a 62.5% thinning pattern. FIG. 17 is an example of the thinning data D4 using the 62.5% thinning pattern shown in FIG. The patterns in the examples of FIGS. 16 and 17 are obtained by alternately arranging five ink ejection regions arranged in a cross shape and one non-ejection region one by one in the vertical direction and the horizontal direction. When such a pattern is used, the number of ink ejection pixels in the thinning data D4 is approximately 62.5% of the number of ink ejection pixels in the raster data D3. If the 62.5% thinning pattern of the example of FIG. 16 is used, printing can be performed darker than the 50% thinning pattern of the example of FIG.

FIG. 18 is an example of a 37.5% thinning pattern. FIG. 19 is an example of the thinning data D4 using the 37.5% thinning pattern shown in FIG. The patterns in the examples of FIGS. 18 and 19 are obtained by alternately arranging one ink ejection region and five non-ejection regions arranged in a cross shape in the vertical direction and the horizontal direction. When such a pattern is used, the number of ink ejection pixels in the thinned data D4 is about 37.5% of the number of ink ejection pixels in the raster data D3. If the 35% thinning pattern of the example of FIG. 18 is used, the mottling can be further suppressed as compared with the 50% thinning pattern of the example of FIG.

FIG. 20 is an example of a 50% thinning pattern different from FIG. In the 50% thinning pattern of FIG. 14, one ink ejection area and one non-ejection area are alternately arranged. On the other hand, the 50% thinning pattern in FIG. 19 is a checkered pattern in which four ink ejection areas arranged in a square shape and four non-ejection areas arranged in a square shape are alternately arranged. . The thinning data D4 may be configured by such a pattern.

Further, the thinning data D4 may be configured by a pattern other than the patterns illustrated in FIGS. For example, in the pattern used for the thinning data D4, there may be a plurality of shapes of ink ejection groups constituted by adjacent ink ejection regions, or a plurality of shapes of non-ejection groups constituted by adjacent non-ejection regions. There may be.

<4. Flow of printing process in tablet printer>
Below, the flow of the printing process according to the rotation angle in the tablet printing apparatus 1 is demonstrated, referring FIG. FIG. 21 is a flowchart showing the flow of printing processing in the tablet printing apparatus 1.

As shown in FIG. 21, in the printing process in the tablet printing apparatus 1, first, a plurality of thinned data D <b> 4 is input from the data processing apparatus 80 to the control unit 70. As a result, the print data holding unit 71 stores the plurality of input thinned data D4 as print data D5 (step S201).

FIG. 22 is a diagram showing an example of a plurality of print data D5 stored in the print data holding unit 71. As shown in FIG. 22, the print data holding unit 71 stores table data in which the rotation angle is associated with each print data D5.

Next, the control unit 70 starts conveying the tablets 9 in the tablet printing apparatus 1 (step S202). After the start of conveyance, the first secant detection camera 32, the second secant detection camera 42, and the third secant detection camera 52 start acquiring images of the tablets 9 to be conveyed, and the acquired image data D6 is sent to the control unit 70. Output. When the image data D6 is input to the control unit 70, the rotation angle detection unit 72 determines the presence / absence, front / back, and rotation angle of the tablets 9 held in the suction holes of the first transport conveyor 41 and the second transport conveyor 51. It detects (step S203). Then, the rotation angle detection unit 72 delivers the detection result D7 to the print data selection unit 73.

Subsequently, the print data selection unit 73 selects, from the print data holding unit 71, the print data D5 to be printed on each tablet 9 held on the first transfer conveyor 41 and the second transfer conveyor 51, based on the detection result D7. Then, it is delivered to the discharge controller 74 (step S204).

Then, the ejection control unit 74 causes the first head unit 43 and the second head unit 53 to perform print processing based on the print data D5 received from the print data selection unit 73 (step S205). Thereby, the image according to the front and back and a rotation angle is recorded on each of the some tablet 9 conveyed.

In this tablet printing apparatus 1, print data D5 for each rotation angle is prepared in advance before performing the printing process. Thereby, after acquiring the detection result D7 of the front and back of the tablet 9 and the rotation angle, the print data D5 can be prepared without delay. Therefore, the processing speed of the printing process in the tablet printer 1 can be improved.

Further, in the tablet printing apparatus 1, not the simple raster data D3 but the thinned data D4 obtained by performing the thinning process on the raster data D3 is used as the print data D5. Thereby, generation | occurrence | production of a mottling can be suppressed and the processing speed of the printing process in the tablet printer 1 can be improved.

<5. Modification>
As mentioned above, although main embodiment of this invention was described, this invention is not limited to said embodiment.

The tablet printing apparatus 1 described above was an apparatus for printing on both sides of the tablet 9 by the first printing unit 40 and the second printing unit 50. However, the tablet printing apparatus of the present invention may be an apparatus that performs printing on only one side of the tablet 9.

In addition, the data processing device 80 and the control unit 70 of the tablet printing device 1 are connected to be communicable, but the present invention is not limited to this. For example, the print data D5 generated by the data processing device 80 may be input to the control unit 70 via a storage medium such as a CD-ROM.

Moreover, although the tablet printing apparatus 1 described above is a separate apparatus from the data processing apparatus 80, the present invention is not limited to this. The tablet printing apparatus of the present invention may include the functions of the respective units of the data processing device 80 in the control unit 70.

Further, the detailed configuration of the tablet printing apparatus 1 may be different from the drawings of the present application. Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Tablet printer 9 Tablet 32 1st secant detection camera 40 1st printing part 42 2nd secant detection camera 43 1st head unit 50 2nd printing part 52 3rd secant detection camera 53 2nd head unit 70 Control part 71 Print data Holding unit 72 Rotation angle detection unit 73 Print data selection unit 74 Discharge control unit 80 Data processing device 81 Vector rotation processing unit 82 Image conversion processing unit 83 Decimation processing unit 431 Head 531 Head D1 Input data D2 Vector rotation data D3 Raster data D4 Thinning out Data D5 Print data

Claims

A data processing apparatus for creating print data for performing print processing on the surface of a tablet with an ink jet head,
A vector rotation processing unit that rotates the input vector data and generates a plurality of vector rotation data corresponding to a plurality of rotation angles;
An image conversion processing unit for converting each of the vector rotation data into raster data;
A data processing apparatus.
The data processing apparatus according to claim 1,
A thinning processing unit that converts each of the plurality of raster data into thinning data having a smaller number of ink ejection pixels than the raster data;
The raster data is data in which the amount of ink discharged is determined for each region arranged in a grid pattern.
The data processing apparatus, wherein an ink ejection area in which ink is ejected in the thinning data is smaller than the ink ejection area in the raster data.
The data processing apparatus according to claim 2, wherein
The thinning processing unit converts the portion of the raster data where the ink ejection regions are continuous into a pattern in which the ink ejection regions and the non-ink ejection regions are alternately arranged to generate the thinning data. .
The data processing apparatus according to claim 3, wherein
The thinning processing unit converts the portion of the raster data where the ink ejection regions are continuous into a pattern in which the square ink ejection regions and the square ink non-ejection regions are alternately arranged to perform the thinning. A data processing device that generates data.
A tablet printing apparatus for printing on the surface of a tablet,
A data processing device for creating print data;
An ink jet head that has a plurality of nozzles that eject ink droplets and that performs a printing process by ejecting the ink droplets toward the surface of the tablet;
A camera that is arranged upstream of the head and detects a rotation angle of the tablet;
A control unit for controlling ejection of the ink droplets from the head;
With
The data processing device includes:
A vector rotation processing unit that rotates the input vector data and generates a plurality of vector rotation data corresponding to a plurality of rotation angles;
An image conversion processing unit for converting each of the vector rotation data into raster data;
Have
The data processing device outputs a plurality of print data based on the plurality of raster data;
The controller is
A print data holding unit for holding a plurality of the print data according to the rotation angle;
A print processing unit that selects the print data from the print data holding unit based on the rotation angle detected by the camera, and causes the head to perform print processing based on the selected print data;
With
The tablet printing apparatus, wherein the print data holding unit holds the plurality of print data input from the data processing apparatus before the rotation angle is detected by the camera.
The tablet printing apparatus according to claim 5, wherein
The data processing device includes:
A thinning processing unit that converts each of the plurality of raster data into thinning data having a smaller number of ink ejection pixels than the raster data;
The raster data is data in which the amount of ink discharged is determined for each region arranged in a grid pattern.
In the thinning data, an ink discharge area in which ink is discharged is smaller than the ink discharge area in the raster data,
The data processing device outputs a plurality of the thinned data as the print data,
The tablet printing apparatus, wherein the print data holding unit holds the plurality of print data input from the data processing apparatus before the rotation angle is detected by the camera.
The tablet printing apparatus according to claim 6,
The thinning processing unit converts the portion of the raster data where the ink discharge areas are continuous into a pattern in which the ink discharge areas and non-ink discharge areas are alternately arranged, and generates the thinning data. .
The tablet printing apparatus according to claim 7,
The thinning processing unit converts the portion of the raster data where the ink ejection regions are continuous into a pattern in which the square ink ejection regions and the square ink non-ejection regions are alternately arranged to perform the thinning. Tablet printing device that generates data.
A data processing method for creating print data for performing print processing on the surface of a tablet with an ink jet head,
a) rotating the input vector data vector to generate a plurality of vector rotation data corresponding to a plurality of rotation angles;
b) converting each of the plurality of vector rotation data into raster data;
A data processing method.
A data processing method according to claim 9, wherein
c) further comprising a step of converting each of the plurality of raster data into thinned-out data having a smaller number of ink ejection pixels than the raster data;
The raster data is data in which the amount of ink discharged is determined for each region arranged in a grid pattern.
The data processing method, wherein an ink ejection area in which ink is ejected in the thinning data is smaller than the ink ejection area in the raster data.
A data processing method according to claim 10, wherein
In the step c), the thinning data is generated by converting a portion of the raster data where the ink discharge areas are continuous into a pattern in which the ink discharge areas and the ink non-discharge areas are alternately arranged. Processing method.
A data processing method according to claim 11, comprising:
In the step c), the thinning data is a pattern in which the ink discharge areas of the raster data are continuously arranged in a pattern in which the rectangular ink discharge areas and the rectangular ink non-discharge areas are alternately arranged. Data processing method generated by conversion.
A tablet printing method in which a printing process is performed on the surface of a tablet by an ink jet head,
A) Vector rotating the input vector data to generate a plurality of vector rotation data corresponding to a plurality of rotation angles;
B) converting each of the plurality of vector rotation data into raster data;
C) a step of holding a plurality of print data corresponding to the rotation angle based on the raster data obtained in the step B);
D) after the step C), detecting the rotation angle of the tablet;
E) After the step D), selecting the print data to be used for print processing from a plurality of the print data based on the rotation angle;
F) printing an image on the surface of the tablet based on the print data selected in the step E);
A tablet printing method.
A tablet printing method according to claim 13,
G) further comprising a step of converting each of the plurality of raster data into thinned data having a smaller number of ink ejection pixels than the raster data after the step B) and before the step C),
In the step C), a plurality of the thinned data are held as a plurality of the print data,
The raster data is data in which the amount of ink discharged is determined for each region arranged in a grid pattern.
The tablet printing method, wherein an ink ejection area in which ink is ejected in the thinning data is smaller than the ink ejection area in the raster data.
The tablet printing method according to claim 14,
In the step G), the thinning data is generated by converting a portion of the raster data where the ink discharge areas are continuous into a pattern in which the ink discharge areas and the ink non-discharge areas are alternately arranged. Printing method.
The tablet printing method according to claim 15, comprising:
In the step G), the thinning data is a pattern in which the ink discharge regions of the raster data are continuously arranged in a pattern in which the rectangular ink discharge regions and the rectangular ink non-discharge regions are alternately arranged. Tablet printing method generated by conversion.